Phase modifier



y 6, 1952 s. MlNNECl 2,595,869

PHASE MODIFIER Filed May 15, 1951 Inventor: Salvatore Minneci,

HisAttbrney.

Patented May 6, 1952 PHASE MODIFIER Salvatore Minneci, Pittsfield,Mass., assignor to General Electric Company, a corporation of New YorkApplication May 15, 1951, Serial No. 226,428

2 Claims.

This invention relates to phase modifiers and, more particularly, toimprovements in adjustable phase modifiers of the non-rotating type.

It is frequently desirable to introduce variable amounts of phasemodifying leading and lagging reactive volt-amperes into an electriccircuit, such, for example, as a commercial frequency powertransmission, or distribution circuit. In accordance with thisinvention, there is provided a novel phase modifier for accomplishingthis purpose which is characterized by utilizing substantially theentire tap range of a transformer winding twice for successivelycontrolling the amount of leading and lagging reactive volt-amperes insuch a way that a tap changing mechanism operating over its entire taprange varies the leading reactive volt-amperes between minimum andmaximum values in one part of the over-all range of operation of thedevice, and the same tap changing mechanism at another time'operatingover its entire tap range varies the lagging reactive volt-amperesbetween maximum and minimum values in the other part of the over-alloperating range of the device.

An object of the invention is to provide a simple and economicalphase-modifier for selectively and non-simultaneously controllingvariable amounts of leading and lagging reactive volt-amperes betweenmaximum and minimum values.

The invention will be better understood from the following descriptiontaken in connection with the accompanying drawing, and its scope will bepointed out in the appended claims.

In the single figure of the accompanying drawing, which illustratesdiagrammatically an embodiment of the invention, there is a mainalternating current circuit I, the phase of the current of which ismodified by the phase modifier indicated generally at 2. Phase modifier2 comprises a multi-tapped transformer 3, of any well known type, whichis illustrated by way of example as a two-winding insulating transformerhaving a primary winding 4 connected across the main circuit I and amulti-tapped secondary winding '5. The taps for the winding 5 comprise apair of spaced taps 6 and I which may be located anywhere on thewinding, and which may be end taps or terminals, as illustrated. Betweentaps E and I are a plurality of electrically, equally-spacedintermediate taps of any desired number, eight being shown, andidentified, respectively, as 8, 9, III, II, I2, I3, I4, and I5. Formaking selective connection with these taps, there is provided a rotarytap changing switch 2 of the dial type which is provided with aplurality of fixed contacts arranged in a circle, and a cooperativemovable contact assembly for making selective connection to orengagement with fixed contacts. In the preferred form of dial switch, asillustrated, there is one more fixed contact than there are intermediatetaps. Thus, the tap changing switch is provided with fixed contacts 8',9', III, II, I2, I3, I4, and I5, connected respectively, and incorresponding sequence, with the like-numbered intermediate taps, andthere is an extra or additional fixed contact I6 which is placed betweenthe contacts 8' and I5 which are connected respectively to theintermediate taps 8 and I5 which are respectively adjacent the spaced orend tap 6 and I. The movable contact assembly is indicated at I! ascomprising a pair of spaced contact fingers I8 and I9, which areinterconnected by a, midtap impedor 20 for permitting tap changingoperations without breaking the transformer secondary circuit, and forproviding intermediate operating steps when the respective contactfingers engage adjacent fixed contacts, so as to place the impedor 20 ina bridging relation with respect to those fixed contacts. The leadingreactive volt-amperes produced by the phase modifier are provided by acapacitive reactor (capacitor) 2| connected to top 6, and the laggingvolt-amperes produced by the phase modifier are provided by an inductivereactor (inductor) 22 connected to the tap I.

For transferring the connections of the capacitor 2| and the inductivereactor 22 to and from the secondary winding 5 by way of the tap changerswitch, there is provided a two-position transfer switch having a commonterminal 23 and a pair of main terminals 24 and 25 connectedrespectively to the inductive reactor 22 and the capacitor 2|. Thistransfer switch may be of any suitable type, such as the simplesinglepole double-throw switch illustrated.

The transfer switch is driven from the movable contact assembly I'! ofthe tap changing switch by an intermittent drive mechanism, such as aGeneva gear mechanism 26, which is so arranged that the transfer switchis moved from one of its circuit closing positions to the other when themovable contact assembly I1, in the middle of its range of motion, ismoving between fixed contacts 8' and I5, or, more particularly, when itis moving across the extra fixed contact I 6, which is between the fixedcontacts 8 and I5.

The extra fixed contact I6 and the movable contact I! are directlyconnected to a conductor 3 21 which connects them to the common terminal23 of the transfer switch.

The operation of the illustrated embodiment of the invention is asfollows: The parts are shown in the position for providing maximumlagging volt-amperes for the circuit I, in that the inductive reactor 22is connected between taps I and 8 so as to have applied to itpractically the entire voltage of the secondary winding 5.

If, now, the movable contact assembly I! is rotated clockwise, as viewedin the drawing, the voltage applied to the inductive reactor 22 isprogressively decreased until when the movable contact assembly I!breaks engagement with the fixed contact I5, there will be zero voltageapplied to the inductive reactor 22 and, hence, there will be zerolagging volt-amperes provided by the phase modifier for the circuit I.Continued clockwise motion of the movable contact assembly I! will nowcause the Geneva gear mechanism 26 to operate the transfer switch fromits illustrated position to its other circuit closing position in whichterminals 23 and 25 are interconnected, and this operation will .becompleted by the time the movable contact assembly I! first contacts thefixed contact 8' of the tap changing switch. As soon as such contact isestablished, minimum finite voltage will be applied to the capacitor 2|so as to provide minimum leading volt-amperes for phase modification ofcircuit l. Continued clockwise rotation of the movable contact assemblyI! will progressively increase the Voltage applied to the capacitor 2|,thus progressively increasing the leading volt-amperes pro vided by thephase modifier, until the equipment reaches the other end of its rangeof operation in which contact assembly I! engages fixed contact While Ihave shown a particular embodiment of my invention, it will beunderstood that I do not wish to be limited thereto, since manymodifications may be made; and I, therefore, contemplate by the appendedclaims to cover any such modifications as fall within the true spiritand scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In combination, a transformer winding provided with a pair of spacedtaps between which there are a plurality of spaced intermediate taps,

a conductor, a rotary tap changing switch for selectively connectingsaid conductor to said intermediate taps in regular sequence except thatsaid switch has a pair of adjacent positions in which it connects saidconductor to intermediate taps which are respectively electricallynearest said spaced taps, a capacitor, an inductor, a transfer switchfor selectively connecting said conductor to said spaced taps throughsaid capacitor and inductor respectively, and an intermittent mechanicaldrive for said transfer switch from said rotary tap changing switch foroperating said transfer switch only when said rotary tap changing switchis moving between its said pair of adjacent positions.

2. In combination, a transformer having a primary winding and asecondary winding, said secondary winding having a pair of end taps andN electrically equally spaced intermediate taps, a dial type tapchanging switch comprising N plus one fixed contacts equally spacedaround a circle and a movable contact pivotally mounted at the center ofsaid circle for selective engagement with said fixed contacts, atwo-position transfer switch having a common terminal and two mainterminals which are respectively connected to said common terminal whensaid switch is in different positions, means for making a directelectrical connection between one of said fixed contacts, said movablecontact and said common terminal, means for connectirv in sequence eachremaining fixed contact to a different intermediate tap, an inductorconnected between one end tap of said secondary winding and one mainterminal of said transfer switch, a capacitor connected between theother end tap of said secondary winding and the other main terminal ofsaid transfer switch, means including a Geneva gear mechanisminterconnecting said movable contact and said transfer switch forcausing said transfer switch to move from one position to the other whensaid movable contact is moving across said one fixed contact, and meansincluding a midtapped impedor for preventing said movable contact fromdisengaging any fixed contact until it engages an adjacent fixedcontact.

SALVATORE MINNECI.

No references cited.

